The ultimate goal of our research program is to develop tactile aids for the deaf and deaf-blind that can serve as substitutes for hearing in speech communication. To the extent that this research is successful, it will enable people who are deaf to achieve substantially improved speech perception, speech producion, and overally language competence. In addition, it will provide increased knowledge about the basic nature of speech communication, about the general capabilities of the tactile sense, about underlying principles for the design of displays, and about sensory substitution and human plasticity. The research proposed in this application is focused on the ability of deaf-blind individuals to communicate through the tactile sense. These individuals have had extensive experience with tactile communication and have evolved the most successful methods yet created. Previous research with the deaf-blind on the Tadoma method (in which speech is perceived by placing a hand on the talker's face) has demonstrated that speech reception through the tactile sense is possible. The basic problems now facing investigators are to determine the ultimate limits of the tactile sense for speech communication, specify the design features that are required for a tactile display to be effective, and develop systems that both provide good performance and function at a distance (i.e., do not require direct physical contact). The specific objectives of the research proposed in this application are to (1) increase our understanding of the Tadoma method; (2) determine the extent to which the results obtained with this method can be improved by supplementing it with additional tactile inputs; and (3) investigate other methods of tactile communication used by the deaf-blind (tactile fingerspelling and tactile signing). The result of this research are expected to show that the performance achieved with Tadoma, although impressive, does not represent the upper limit on the tactile reception of speech, and to provide important background for the development of artificial systems.